Fault locatio o shielded cables: Electromagnetic modelling and improved measurement data processing

This paper analyses the performance of the time domain reflectometry (TDR) technique he it is applied to the locatio of faults o cables. Different types of defects, hich ca arise o coaxial cables, are modelled and their reflectio coefficients are calculated. The results, validated by experimental data, are compared to the typical noise that affects this kind of measurement to assess the sensitivity of the technique. Shield damage to a shielded t isted pair and a shielded multi ire cable is also examined: these examples represent more critical situations because the effect of cable and mismatching losses limits the dynamic range of the measurement. I both cases, the TDR allo s us to locate faults that strongly affect the propagatio of the signal o the transmission line, but the reflections produced by small defects are ofte masked by the noise. A data processing technique based o the compariso ith a reference measurement and the use of the statistical correlatio are then implemented. I this ay, the reflections produced by the faults are much more visible and a overall enhancement of the technique sensitivity is achieved.